1. Field of the Invention
The present invention relates, in general, to residential electrical and control systems, and more particularly, to an electrical junction box for use in providing an all-in-one box containing a fixed electrical circuit or component wiring and electrical components to facilitate connection of a forced-air furnace to a residential power source such as a service panel and connection of one or more heating and ventilation appliances often installed as part of a residential heating, ventilation, and air conditioning (HVAC) system to the service panel and/or to the furnace electrical system.
2. Relevant Background
A large percentage of homes and residential buildings in cooler climates use forced-air heating systems including a furnace with a blower to circulate heated air. The furnace is powered by electricity provided by a power source in the building or home such as from connection with a service panel. Often, a number of other heating, ventilation, and air conditioning components operate in conjunction with the furnace to condition air circulated throughout the residence. For example, an electronic air cleaner (EAC) may be provided to remove particulates in circulated air. A humidifier may also be included in the residential HVAC system to control humidity levels inside the building served by the HVAC system. Additionally, condensate pumps are often provided to remove water that condenses (often in an air conditioner) to prevent flooding near the furnace. Often, these additional appliances associated with the furnace are called fixed or ancillary appliances.
The ancillary appliances are typically powered by a connection to the service panel with their operations being directly or indirectly linked to the operation of the furnace. Many furnaces include an electrical junction box for connecting to the service panel and also providing control wires or connection points for fixed appliances that need to operate in conjunction with the furnace. For example, control wires may be provided for tying operation of a furnace blower motor with operation of an electric air cleaner (EAC) and/or a humidifier. The wiring and configuration of the HVAC and associated equipment and fixed appliances must be completed to applicable local codes or laws. In the United States, the wiring needs to comply with the National Electrical Code (NEC) requirements for residential HVAC systems. An example of code requirements include the provision of a ground fault circuit interrupt (GFCI) receptacle within sight of the furnace for providing power to tools, such as tools used in installing a furnace or fixed appliances or performing maintenance. Another code requirement is that an overcurrent, short-circuit protection device and a switch (e.g., a 125V box cover unit for a plug fuse with a proper ampere rating) be provided as a disconnecting means between the service panel and these components for automatically and selectively interrupting power to the furnace and to particular fixed appliances.
Wiring of residential HVAC systems at initial installation and during an upgrade or repair of the system can be a time consuming, and therefore, expensive task. Additionally, wiring the HVAC system correctly to appropriate codes and in a safe and effective manner is often difficult even for experienced electricians that may not be familiar with HVAC systems. During initial installation or installation of a replacement system, a standard furnace electrical hook up can take from one to four hours for an electrician depending upon the location of the furnace, the configuration of the furnace, and the number of ancillary appliances that are included in the HVAC system.
Presently, the furnace is wired to the service panel with an overcurrent protection device (e.g., a fuse) with a power switch wired between the furnace electrical junction box and the service panel. Then, each additional appliance and/or device is separately wired to the service box and/or to the overcurrent/disconnecting device and if appropriate, to the control wires provided in the furnace electrical junction box. This results in three or more boxes and a number of fittings being mounted near the furnace (such as on the return air duct near the furnace) and wiring running from each box to the various fixed appliances and to the furnace. The installing technician or electrician must assemble these boxes, fittings, and parts in a manner that meets national and local codes. Additionally, the furnace and appliance wiring must be done to manufacturers requirements and in a particular circuit configuration to assure proper operation. This is a time consuming process and mistakes can result in safety problems, flooding, product damage, or simply result in wasted power due to running appliances at incorrect times (such as by running the EAC or humidifier when the furnace blower motor is not running). Repairing or upgrading existing systems can also be time consuming with the electrician being forced to first understand an existing installation and wiring configuration and then installing new components to comply with codes and to be wired in the HVAC system to support proper operation of existing components as well as new components. A common upgrade is the addition of EACs or humidifiers, and these must be wired to the furnace controls to operate in conjunction with the furnace. Again, even experienced electricians find this to be a time-consuming process in which hurrying can result in unacceptable wiring mistakes and safety or operational problems.
Hence, there remains a need for a product or method for facilitating electrical wiring of HVAC systems including wiring furnaces, fixed appliances, and other components (such as overcurrent and switch units and GFCI receptacles) to residential power supplies such as service panels and to each other as required per national and local codes and for proper system and component operation.
The present invention addresses the above problems by providing an electrical hook-up junction box for furnaces and associated equipment that provides a single electrical connection to the furnace branch circuit of the service panel and easy and fast to wire connections to the furnace and receptacles for a number of fixed appliances. In one embodiment, the junction box is configured with an incoming power terminal block, an outgoing power terminal block, and a ground bar for providing convenient connections. For example, the incoming power terminal block is connected to the hot and neutral of the branch circuit from the service panel and the ground bar is connected to the ground from the branch circuit. Preferably, the blocks or strips and ground bar are labeled for proper hook up and when installed, the furnace is provided power by connection to the outgoing power terminal block and ground bar. A switch and fuse unit is connected to the terminals and ground bar to provide overcurrent or overload protection to the furnace and to allow power to be manually disconnected. Receptacles are provided for fixed appliances, such as a condensate pump, an EAC, and a humidifier with connections provided between the incoming and outgoing power terminal strips and ground bar and the receptacles to insure proper operation.
Control wires are also provided to connect the control terminals of the furnace electrical junction box and receptacles for the EAC and the humidifier such that these receptacles are only operable or hot when the blower motor is operating. Further, a GFCI outlet (such as one with two receptacles) is provided upstream of the switch and fuse unit to be available when power is needed to work on the system. The condensate receptacle is wired in the junction box upstream of the switch to provide uninterrupted power to the condensate pump when it is plugged into the receptacle. In this manner, the junction box of the invention provides an all-in-one electrical hook up box for use with most forced-air furnaces that significantly simplifies initial installation and repair of the furnace and associated appliances and devices by providing a self-contained, pre-configured power supply and control circuit and connection terminals and ports.
More particularly, an electrical junction box is provided for use in electrically hooking up a forced-air furnace and providing power and control signals to associated fixed appliances whether installed with the furnace or at a later time. The junction box includes a panel connection adapted for connecting to a cable from a service panel or other power source, e.g., connecting with the hot wire, the neutral wire, and the ground from the panel. A furnace connection is also provided for ready connection of a furnace cable typically including a hot wire, a neutral wire, a ground, and a number of control wires (such as a humidifier control wire and an EAC control wire). The connections may include a number of well-labeled terminals on an incoming power terminal strip, an outgoing power terminal strip, and a ground bar mounted within the junction box. A disconnect switch is mounted in the junction box and wired in series between the hot wire connection portion of the panel connection and the hot wire connection of the furnace connection and is manually operable to selectively interrupt electricity flow from the service panel connection to the furnace. A GFCI device with one or more receptacles is mounted within the junction box and wired to the hot wire connection portion of the panel connection on a line side of the disconnect switch. A condensate pump outlet with a receptacle is also mounted in the junction box and wired to the hot wire connection portion of the panel connection on the line side of the disconnect switch to allow a pump plugged into the receptacle to operate regardless of the position of the disconnect switch. A humidifier outlet and an EAC outlet both with receptacles are also mounted in the junction box and are coupled directly or indirectly (such as via a connector or node and a conductor) to the connections of the furnace connection used for the corresponding control wires from the furnace.